Floating Oxygen-Injection Aerator Speed Control for Lower Energy Use
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Solution Overview
Problem
Existing water treatment devices for injecting oxygen into purification basins consume unnecessary electricity due to maintaining constant agitation speed and gas flow rates, despite varying oxygen requirements throughout the day, leading to inefficient energy use.
Innovation Solution
Implementing a frequency converter in the control cabinet to vary the motor's power supply frequency and rotation speed of the stirring/dispersion/injection mobiles, allowing the device to operate within a range of ±15% of the nominal speed to optimize energy consumption based on real oxygen demand.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the device operates at nominal speed continuously, then the mixing capacity and gas transfer efficiency are maintained, but the energy consumption increases unnecessarily
Solution Approach 1:
The patent applies dynamics by enabling the aerator to operate at variable speeds rather than a fixed nominal speed. The control unit adjusts the rotation speed of the propeller based on real-time oxygen demand measurements, allowing the system to adapt its mixing capacity dynamically. This resolves the contradiction by maintaining adequate mixing only when needed while reducing energy consumption during periods of lower oxygen demand.
Solution Approach 2:
The patent changes the operational parameter of rotation speed from a constant nominal value to a variable parameter adjusted according to oxygen demand. By modifying the speed parameter in response to measured oxygen levels, the system optimizes the balance between mixing capacity and energy consumption, avoiding unnecessary energy use when high mixing performance is not required.
2Use of energy by moving object
If the device operates at nominal speed continuously, then the gas transfer efficiency is maintained, but the energy consumption increases unnecessarily
Solution Approach 1:
The patent implements feedback control by using a dissolved oxygen sensor to continuously measure oxygen levels in the water and feeding this information back to the control unit. The control unit then adjusts the propeller speed accordingly, reducing energy consumption when oxygen levels are sufficient and increasing speed only when additional oxygen transfer is needed. This feedback mechanism resolves the contradiction between energy consumption and gas transfer efficiency.
3Use of energy by moving object
If the agitation speed is reduced, then the energy consumption decreases, but the mixing capacity may become insufficient
Solution Approach 1:
The system dynamically adjusts agitation speed based on actual oxygen demand rather than operating at a fixed reduced speed. When oxygen demand increases (as detected by the sensor), the propeller speed increases automatically to maintain adequate mixing capacity. This dynamic adjustment allows the system to consume less energy during low-demand periods while ensuring mixing capacity is sufficient when needed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Reduces energy consumption by 16% while maintaining equivalent gas transfer efficiency and mixing capacity, by adjusting the device's operation to match varying oxygen requirements.
Implementation Method 1
a frequency converter, intended to vary the power supply frequency to the motor and therefore the rotation speed of the shaft on which the stirring/dispersion/injection mobile(s) are mounted
Implementation Method 2
a propeller for mixing and dispersing the injected gas in the liquid
Data Source
Figure 1
AI summary
A method for managing the operation of an oxygen injection device in a treatment basin, oxygen notably used by the biomass present in the basin to consume the pollution present in an effluent to be treated contained in this basin, the device being characterized by the following components and functionalities: - the device is positioned on the surface of the basin, and equipped with a system allowing it to remain floating above the liquid; - it includes a drive device, intended to be positioned above the liquid, preferably provided with a vertical or inclined output shaft, the shaft equipped at its end with at least one moving part for mixing and dispersing the injected gas such as a three-bladed propeller; - it includes a system for injecting a gas containing oxygen;method characterized in that the rotational speed of the shaft is varied using a frequency inverter, the applied speed variation being between +15% and -15% of the nominal speed of the equipment, and more preferably between +10% and -10% of the nominal speed of the equipment, i.e. under conditions where the motor is supplied at the network frequency without modification, in order to optimize electrical consumption according to the need for injection of oxygen-containing gas and the mixing capacity required for the treatment basin where the equipment is installed.